The cell and culture viability of concentrates of the microalga Nannochloropsis oculata were assessed after storage for a period of 16 weeks at -18, 0 and 5ºC. The concentrates were obtained from the crop of N. oculata, which was harvested at the start of the seasonal growth period using a process of flocculation. Flocotac Plus was used as the flocculation agent, achieving flocculation of 90% of the suspended microalgae. It was observed that the chemical process did not affect the number of live cells. The concentrate stored at -18ºC presented slow freezing, which deteriorated the cells and therefore reduced cell viability after five weeks (75%). The concentrates stored at 0 and 5ºC showed cell viability over 97% after the 16 weeks. Culture viability was only seen in the concentrates stored at 0 and 5ºC, which showed specific growth rates similar to those of the control culture. It may be concluded that it is possible to use flocculates stored at 0 and 5ºC after 16 weeks as inoculum for mass crops of N. oculata for food, green water and other uses.

Abstract
Latin American Journal of
Aquatic Research,
43 (2) May 2015 (SPECIAL ISSUE)
Assessment of the shelf-life of Nannochloropsis oculata flocculates stored at different temperatures.